Tapered cutting edge for digging and carrying scraper and associated apron



2,729,001 ND CARRYING 2 Sheets-Sheet 1 INVENTOR.

J." ADA/"1s Arran/Vey;

GOGO

Jan. 3, 1956 w. J. ADAMS,

TAFERED CUTTING EDGE FOR DIGGING A SCRAPER AND ASSOCIATED APRON Filed Aug. 14, 195] Jan. 3, 1956 w. .1. ADAMS 2,729,001

TAPERED CUTTING EDGE FOR DIGGING AND CARRYING SCRAPER AND ASSOCIATED APRON Filed Aug. 14, 1951 2 Sheets-Sheet 2 1N VEN TOR. VV/L MM J: 14o/IMJ United Safes Par-elif o TAPERED CUTTING EDGE FOR DIGGING AND CARRYING SCRAPER AND ASSOCIATED APRON William J. Adams, Santa Cruz, Calif., assigner, by rnesne assignments, to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application August 14, 1951, Serial No. 241,745

1 Claim. (ci. :tr- 141) This invention relates to improvements in cutting edges and cutters and more particularly to a tapered cutting edge for a digging and carrying scraper.

One of the objects of the present invention is to provide in a scraper of the type described a'cutter adapted to cut more easily in hard soil and to form a better heaped center load in said scraper.

Another object of the present invention is to provide in a scraper of the type described a coacting cutter and apron to provide a larger throat capacity for the cutter, a closer seal between the cutter and the apron, and an easier closing action for the apron when it bites away the material on the cutter.

Other features of this invention. reside in the arrangement and design of the parts for carrying out their appropriate functions. Y

Other objects and advantages of this invention will be apparent from the accompanying drawings and description and the essential features will be set forth in the appended claims.

In the drawings,

Fig. 1 is a side elevational view of the digging and carrying scraper having the novel cutter and apron of this invention;

Fig. 2 is an enlarged fragmental top view of Fig. l taken along the line 2 2 of Fig. 1;

Fig. 3 is an enlarged sectional view taken along the line 3 3 of Fig. l and showing a heaped center load in dot-dash line in the scraper bowl;

Fig. 4 is an enlarged vertical sectional View taken along the line 4 4 of Fig. 3 with the conventional apron lip and the dirt depth on the cutter 'shown in dot-dash lines;

Fig. 5 is an enlarged vertical sectional view taken along the line 5 5 of Fig. 3; while Fig. 6 isa reduced sectional view taken along the lin 6 5 of Fig. 4 with the apron elevated and earth being cut.

While the novel type cutter and apron of this invention might be adapted to various types of machines, I have chosen to show the same as applied to a digging and carrying scraper described and claimed in the copending U. S. patent application of William J. Adams entitled Scraperf Serial No. 111,496, led August 20, 1949, now Patent No. 2,674,815. The scraper, generally indicated at 10, is of the conventional type of digging and carrying scraper and is fully disclosed in said patent application.

The pull yoke 11 pivotally attached to the scraper is mounted by a pivotal hitch' to the prime mover or tractor which pulls the scraper and supports the front end of the scraper. Rear wheels 12 support the rear end of the scraper. The transportable scraper bowl, mounted between the rear wheels 12 and the tractor, has side walls to retain the dirt or other scraper load and is open at its forward end. An ejector 14 pivoted at 15 in the bowl 13 oscillates in a counter-clockwise direction (Fig. 1) to discharge the contents of the bowl. The cutter, generally indicated at 16, is located on the bottom of the bowl in front of or ahead of the pivot point 15. Apron f"ice 4 17 at the front of the bowl is pivoted to the bowl side walls at pivot points 18 to close the open front end of the scraper bowl. These are the basic elements of the conventional digging and carrying scraper. This invention relates to the shape of the cutter 16 and the coacting lip of apron 17. i

The cutter 16 wil now be described. The cutter has a cutter base 20 attached to the opposite side walls of the bowl and to a zone near the ejector pivot axis 15 to form a rigid structure. A cutting blade is attached to this cutter base and has a tapered form. This cutting blade can, of course, be a one-piece, integral blade or can be made up of a series of blade sections. The latter form has been chosen to be illustrated in the drawings of this application and has novel features as defined in the claims.

The cutting blade in Fig. 3 consists of a center blade section 22 and two end blade sections 23 and 24. The center blade section 22 has a forward cutting edge or leading edge which extends perpendicular to the general direction of cutter movement when loading the scraper. it has a rectangular, double-edged blade formation. This center blade section 22 is attached to the cutter base 20 by bolts or any other type fastening means desired. Since the blade section 22 is double-edged and rectangular, it may readily be turned over on the cutter base 20 and then clamped in position so as to present the other parallel cutting edge and to give added wear life.

The end blade sections 23 and 24 are each contiguous to and abut an end of the center blade section. The end blade sections are identical in shape. Each end blade section has a forward cutting edge or leading edge that is outwardly and rearwardly and upwardly inclined with respect to the general direction of travel of the cutting blade. Each end blade section is of identical rhomboid shape, double-edged on their longer sides and removably mounted on the cutter base 20. This removable mounting takes the form of bolts in the drawings but any other type of mountings desired can be used. Since the end blade sections are identical in shape they maybe interchanged or turned end for end on the cutter base 20 so that all four cutting edges of the two end blade sections can be used. Hence, the double-edged blade sections 23 and 24, being of similar shape, have long cutting edge life. Although the drawings illustrate each end blade section of a rhomboid shape having no right angles, the end blade sections may be rectangular in formation if the abutting ends of the center blade section 22 converge slightly rearwardly. In this case, the center blade section would not be reversible but the end blade sections would be reversible.

The drawing discloses the center blade section 22 and the two end blade sections 23 and 24 to be coplanar. The cutting blade or blade sections are downwardly and for wardly inclined relative to the general direction of cutter movement or digging motion. In Fig. 1, lthe cutter and the digging and carrying scraper move toward the left. When the blade sections are coplanar and in the position shown lin Fig. 2, definite relationships exist between the cutting angle and the shape of the end blade sections. The angle betweenthe leading edge of an end bladesection and the adjacent edge abutting the center blade section is complementary to the cutting angle between the leading or forward cutting edge of the end blade section and a line parallel to the leading edge of the center blade section. This angle is measured in the common plane of the blade sections 22, 23 and 24. Also, when these blade sections are co-planar (as illustrated), the tapered cutting edges of the cutting blade or blade sections 23 and 24 converge toward the leading edge of the blade formed by the cutting edge on blade section 22. It might also be said that these tapered cutting edges on sections 23 and T24 are outwardlysland-npwardly inclined from'the leading edge of the center blade section 22.

This tapered cutting blade formation has several advantages. First, the cutting blade in Fig. 3 tends to form a better -heaped center :load :in the scraper bowl. he upwardly-inclined center bladefsection22 cuts, since it is lowerthan the othe'rblade sections, a thicker slab of material Vthan theupwardlyinclined endseetions 23-and 24 since'itscutting edgeiextends downwardly below those of sections 23 and 24. This thicker slab ofrcut material in the center of thebowl willtendlto heap up and ,form a better heaped center load-as shown as 25 ,in Fig. 3 by the .dot-dashdines. .The yload will Vnot be jammed against the ,sides and any of the load rolling oil?l the heaped center will rollfgently down against the sides ofthe bowl instcadof-.being .jammed against them. Since the load is not .so tightly-packed. or Vjammed; against vthe sides,v agpivoted ejector -14can-easily.dump,or eject a load. Second, the .upwardlyftapered cuttingedges ofsections 23 and 24 with the low centerportion of the cuttingl edge on section I.

22 permit thetaking of anarrower .cut than the straightacross cutting blade of-the conventional scraper when the depth of cut is notfgreatenoughvto require the full length of the `cutting-edges of-sections `23, 24. A deeper cut can be also taken, if desired, since the tapered cutting blade-design land thenarrower cut insure a larger. cutting force per inch of cutting width .than the conventional cutting blade.

The apron 17 is pivotally-mounted .at 18, 1S atthe front of the scraper bowl .13. The lower lip 26 of the apron substantially conforms in shape to the cutting edges, as seen in Figs. 2 and 3, and is adapted to contact the cutting blade sections along the full width of the bowl and close behind the blade cutting edges. The

apron lip 26 is substantiallyparallel to the cutting edges, 5

as seen in Fig. i3, Iwhen vthe lip `and blade contact. The bladecontacting edge of the lip 26 lies all in one plane.

The .shape of this apron -lip has many advantages` First, .the lip 26 provdes acloser seal with the-blade to prevent the escape of the load from the scraper bowl. Second, the shape of the lip provides a larger throat opening when-the apron 17'is lifted during thecutting operation. This larger throat opening-is over the center blade section 22 where it is most needed since the center blade section takes vthe thickest or'thedeepest cut. rPhis larger throat opening results frorna difference in radius between the kapron,pivotpointsl, 1-8 and-different points on the apron lip 26. This relationship is most clearly shown in Fig. 3, where the axis of pivot points .18, lll is indicated by a dot-dashlinevA. The portion of lip ,26 in contact with'the center blade section '.22 is al greater distance from axis Athan the ,portion of the lip .26,in contact with the outer .edge ofaend blade sections Zd'and Z4. Theportion of the lip with the larger radius moves a greater'distance for .ajgiven .angular "displacement ofthetapromand hence,

alarger throatopening exists adjacent thiszportion of the lip, as seen in Fig. v6. Third, the conforming lip 260i the apron makes it easierto close the apron when the cutting blade is lifted out of the cut. It does ,notfhave to bite away as much -earth or material on the cutting blade as the conventional `apronlip. In Fig-4 of the drawings, the contour of the previously cut earth is shown lying on the cutting blade as the ,cutting bladeislifted out of .the cut. (The conventional,.straight-across apron lip is -shown at 27 bythe dot-dashflines.) VIn Yorder lfor this straight apron'liptoprevent the escape of dirt-from 'the outer ends of the end blade Vsections"23::aud 24, the apron llip 27 rnust'contact thecenter blade 'section 22 a 4 considerable 'distanceback'frorn the leading cutting edge. The apron lip 27 of the conventional type must then bite through a thicker amount of earth resting on the center blade section, as shown in Fig. 4. This added resistance may prevent the apron from closing. With the novel apron lip 26 of this invention, this diiculty does not exist since the apron lip '26 `engages the center blade section 22 fairly close .to the leading cutting edge and docs not have^to bite away very .much of the earth remaining on the cutting blade.

Some of the advantages of this invention are realized if ythe whole blade is not co-planar as long as the apron lip matches the cutting'blade in a similar manner to that set forth above, and if because the distal ends of the cutting blade are. adapteditocreate a heaped Vcenter load the blade is upwardly inclined from the center portion of the blade. In other words, in its broadest aspect, my invention contemplates a cutter blade which takes a deeper cut :at .the :center, combined with `an vapron .lip which closely ,conforms to `thencoutour of such blade close;behind the leading edge thereof.

What I clairn is:

In adigging andcarrying scraper, a scraper bowl open at its .forwardfend and having a ,cutter blade .mounting base behind said open end, a Vrectangular center blade section and two rhomboid end blade sections, one on each side of saidcenter blade section, all of said blade sections-lyingina common plane, each of said blade sectionshaving :leading and ,trailingcutting edges, a line of spaced vbolt vholesin eachsectionfextending parallel to one of its associated cutting edges for detachably mounting -said ,sect-ion on said base, the leading cutting edge of said .center zbladesect-ion extending perpendicular to the direction of movement and each of said end sections extending Ylaterally .outwardly and upwardly and rearwardlywith respect \.to:digging motion of said scraper, and the forward internal angleof Aeach saidrhomboid end section at the end abutting said center section being complementary to the angle between the leading edge of said end sect-ionand -a lineparallel to the leading edge of said center section, said angles `being measured in said common plane, whereby said blade sections may be reoriented on said base .sothatthe trailing cutting edges maybe used, the center portion of said blade adapted to make a deeper cut than1the .end portions thereof, an apron pivotally mountedonsaid bowl aboutan aXis-generallyparallel to the leading cutting edge of. said center blade section for opening or closing said open end, said apron having a lip having portions thereof oriented similarly `to the leading cutting-edges of said sections and adapted to-engage said` sectionsin .closed position, the lip portion engageable with said center section being Vlocated fartherfromfsaid pivotalaX-is thanthelip portions engageable with .said end blade sections, saidilip andcutting edge Yconstruction preventing escape of the bowl contents in the closed position, .providingalarger throat opening over the .center blade .section-than-overthe end sections, and providing easy apron closing when the bowl yis loaded.

-References'Cited'in thefile of thispatent UNITED STATES PATENTS 1,333,816 -Mossman.- .Mar. 16, 19.20 083,307 :Schultz June 8, 1937 ,2,154,1503 .French :etal .-Aprl A18, 1939 .2,260,388 Le Bleu... Oct. '28, 1941 ,2,394,786 .Armington:et:a1. Dec. .1.5, 1942 :2.3295831 .Ferguson .LSept. 21,11943 2,349,576 Daniels- May 23, 1944 

